code: def _read_csv(log_dir, xcolumn, ycolumn):
      """Read csv files and return xs and ys.
  
      Args:
          log_dir (str): Log directory for csv file.
          xcolumn (str): Which column should be the JSON x axis.
          ycolumn (str): Which column should be the JSON y axis.
  
      Returns:
          list: List of x axis points.
          list: List of y axis points.
  
      """
      xs, ys = [], []
      with open(os.path.join(log_dir, "progress.csv"), "r") as csv_file:
          for row in csv.DictReader(csv_file):
              xs.append(float(row[xcolumn]))
              ys.append(float(row[ycolumn]))
  
      return xs, ys
  
file_path: garage/benchmarks/src/garage_benchmarks/helper.py
imports: import csv
  import functools
  import json
  import os
  import pathlib
  import random
  import subprocess
  from google.cloud import storage
  import matplotlib.pyplot
  import numpy
  import tensorflow
label_desc: Use image node_id 4 for calling a global function with example usage: _read_csv(log_dir, xcolumn, ycolumn) and returns: xs,  ys